The technology of virtually providing a stereophonic sound field to a listener using two speakers has been developed in recent years. For example, the method of canceling crosstalk which occurs when outputting (reproducing) a binaurally recorded audio signal from two speakers is widely known (see Patent Literature (PTL) 1 as an example).
The technology of providing a virtual sound field to a listener using a speaker array is known, too (see PTL 2 as an example).